U.S. Army Special Forces and Afghan commandos have captured a major ISIS stronghold in Afghanistan, defense officials told Stars and Stripes on Saturday, effectively depriving the terror group of its local capital in one of the largest joint operations ever conducted between U.S. and Afghan special operations forces.

The U.S. military Tuesday morning announced the death of a service member in a firefight that injured four more American troops in Afghanistan’s Nangarhar Province on Jan. 1 — the first U.S. combat fatality of 2018, and a stark reminder of the challenges facing U.S. troops in the year ahead.

When the U.S. military dropped the GBU-43, known as the MOAB — short for Massive Ordnance Air Blast, or it’s more grabby nickname, the mother of all bombs — on a network of tunnels belonging to Islamic State militants in Afghanistan, it made headlines the world over. Reports of the April 13 strike in Nangarhar province in Afghanistan ran on every major outlet — some set to the uber-patriotic song stylings of Toby Keith, underscoring the bomb’s role as both a tactical asset and a propaganda tool.

On Friday, the Department of Defense announced a 15-6 investigation into the deaths of two Army Rangers killed during a grueling three-hour firefight in the eastern Nangarhar province of Afghanistan, citing “friendly fire” as a possible cause of death, according to a statement released by U.S. Forces-Afghanistan.